net/base/features.h

// Copyright (c) 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_BASE_FEATURES_H_
#define NET_BASE_FEATURES_H_

#include "base/feature_list.h"
#include "base/metrics/field_trial_params.h"
#include "net/base/net_export.h"
#include "net/net_buildflags.h"

namespace net {
namespace features {

// Toggles the `Accept-Language` HTTP request header, which
// https://github.com/WICG/lang-client-hint proposes that we deprecate.
NET_EXPORT extern const base::Feature kAcceptLanguageHeader;

// Enables TLS 1.3 early data.
NET_EXPORT extern const base::Feature kEnableTLS13EarlyData;

// Enables DNS queries for HTTPSSVC or INTEGRITY records, depending on feature
// parameters. These queries will only be made over DoH. HTTPSSVC responses may
// cause us to upgrade the URL to HTTPS and/or to attempt QUIC.
NET_EXPORT extern const base::Feature kDnsHttpssvc;

// Determine which kind of record should be queried: HTTPSSVC or INTEGRITY. No
// more than one of these feature parameters should be enabled at once. In the
// event that both are enabled, |kDnsHttpssvcUseIntegrity| takes priority, and
// |kDnsHttpssvcUseHttpssvc| will be ignored.
NET_EXPORT extern const base::FeatureParam<bool> kDnsHttpssvcUseHttpssvc;
NET_EXPORT extern const base::FeatureParam<bool> kDnsHttpssvcUseIntegrity;

// If we are still waiting for an HTTPSSVC or INTEGRITY query after all the
// other queries in a DnsTask have completed, we will compute a timeout for the
// remaining query. The timeout will be the min of:
//   (a) |kDnsHttpssvcExtraTimeMs.Get()|
//   (b) |kDnsHttpssvcExtraTimePercent.Get() / 100 * t|, where |t| is the
//       number of milliseconds since the first query began.
NET_EXPORT extern const base::FeatureParam<int> kDnsHttpssvcExtraTimeMs;
NET_EXPORT extern const base::FeatureParam<int> kDnsHttpssvcExtraTimePercent;

// Enables optimizing the network quality estimation algorithms in network
// quality estimator (NQE).
NET_EXPORT extern const base::Feature kNetworkQualityEstimator;

// Splits cache entries by the request's NetworkIsolationKey if one is
// available.
NET_EXPORT extern const base::Feature kSplitCacheByNetworkIsolationKey;

// Splits host cache entries by the DNS request's NetworkIsolationKey if one is
// available. Also prevents merging live DNS lookups when there is a NIK
// mismatch.
NET_EXPORT extern const base::Feature kSplitHostCacheByNetworkIsolationKey;

// Partitions connections based on the NetworkIsolationKey associated with a
// request.
NET_EXPORT extern const base::Feature
    kPartitionConnectionsByNetworkIsolationKey;

// Partitions HttpServerProperties based on the NetworkIsolationKey associated
// with a request.
NET_EXPORT extern const base::Feature
    kPartitionHttpServerPropertiesByNetworkIsolationKey;

// Partitions TLS sessions and QUIC server configs based on the
// NetworkIsolationKey associated with a request.
//
// This feature requires kPartitionConnectionsByNetworkIsolationKey to be
// enabled to work.
NET_EXPORT extern const base::Feature
    kPartitionSSLSessionsByNetworkIsolationKey;

// Enables sending TLS 1.3 Key Update messages on TLS 1.3 connections in order
// to ensure that this corner of the spec is exercised. This is currently
// disabled by default because we discovered incompatibilities with some
// servers.
NET_EXPORT extern const base::Feature kTLS13KeyUpdate;

// Enables CECPQ2, a post-quantum key-agreement, in TLS 1.3 connections.
NET_EXPORT extern const base::Feature kPostQuantumCECPQ2;

// Changes the timeout after which unused sockets idle sockets are cleaned up.
NET_EXPORT extern const base::Feature kNetUnusedIdleSocketTimeout;

// Enables the built-in resolver requesting ESNI (TLS 1.3 Encrypted
// Server Name Indication) records alongside IPv4 and IPv6 address records
// during DNS over HTTPS (DoH) host resolution.
NET_EXPORT extern const base::Feature kRequestEsniDnsRecords;
// Returns a TimeDelta of value kEsniDnsMaxAbsoluteAdditionalWaitMilliseconds
// milliseconds (see immediately below).
NET_EXPORT base::TimeDelta EsniDnsMaxAbsoluteAdditionalWait();
// The following two parameters specify the amount of extra time to wait for a
// long-running ESNI DNS transaction after the successful conclusion of
// concurrent A and AAAA transactions. This timeout will have value
// min{kEsniDnsMaxAbsoluteAdditionalWaitMilliseconds,
//     (100% + kEsniDnsMaxRelativeAdditionalWaitPercent)
//       * max{time elapsed for the concurrent A query,
//             time elapsed for the concurrent AAAA query}}.
NET_EXPORT extern const base::FeatureParam<int>
    kEsniDnsMaxAbsoluteAdditionalWaitMilliseconds;
NET_EXPORT extern const base::FeatureParam<int>
    kEsniDnsMaxRelativeAdditionalWaitPercent;

// When enabled, makes cookies without a SameSite attribute behave like
// SameSite=Lax cookies by default, and requires SameSite=None to be specified
// in order to make cookies available in a third-party context. When disabled,
// the default behavior for cookies without a SameSite attribute specified is no
// restriction, i.e., available in a third-party context.
// The "Lax-allow-unsafe" mitigation allows these cookies to be sent on
// top-level cross-site requests with an unsafe (e.g. POST) HTTP method, if the
// cookie is no more than 2 minutes old.
NET_EXPORT extern const base::Feature kSameSiteByDefaultCookies;

// When enabled, cookies without SameSite restrictions that don't specify the
// Secure attribute will be rejected if set from an insecure context, or treated
// as secure if set from a secure context. This ONLY has an effect if
// SameSiteByDefaultCookies is also enabled.
NET_EXPORT extern const base::Feature kCookiesWithoutSameSiteMustBeSecure;

// When enabled, the time threshold for Lax-allow-unsafe cookies will be lowered
// from 2 minutes to 10 seconds. This time threshold refers to the age cutoff
// for which cookies that default into SameSite=Lax, which are newer than the
// threshold, will be sent with any top-level cross-site navigation regardless
// of HTTP method (i.e. allowing unsafe methods). This is a convenience for
// integration tests which may want to test behavior of cookies older than the
// threshold, but which would not be practical to run for 2 minutes.
NET_EXPORT extern const base::Feature kShortLaxAllowUnsafeThreshold;

// When enabled, the SameSite by default feature does not add the
// "Lax-allow-unsafe" behavior. Any cookies that do not specify a SameSite
// attribute will be treated as Lax only, i.e. POST and other unsafe HTTP
// methods will not be allowed at all for top-level cross-site navigations.
// This only has an effect if the cookie defaults to SameSite=Lax.
NET_EXPORT extern const base::Feature kSameSiteDefaultChecksMethodRigorously;

// If this is set and has a non-zero param value, any access to a cookie will be
// granted Legacy access semantics if the last access to a cookie with the same
// (name, domain, path) from a context that is same-site and permits
// HttpOnly access occurred less than (param value) milliseconds ago. The last
// eligible access must have occurred in the current browser session (i.e. it
// does not persist across sessions). This feature does nothing if
// kCookiesWithoutSameSiteMustBeSecure is not enabled.
NET_EXPORT extern const base::Feature
    kRecentHttpSameSiteAccessGrantsLegacyCookieSemantics;
NET_EXPORT extern const base::FeatureParam<int>
    kRecentHttpSameSiteAccessGrantsLegacyCookieSemanticsMilliseconds;

// Recently created cookies are granted legacy access semantics. If this is set
// and has a non-zero integer param value, then for the first (param value)
// milliseconds after the cookie is created, the cookie will behave as if it
// were "legacy" i.e. not handled according to SameSiteByDefaultCookies/
// CookiesWithoutSameSiteMustBeSecure rules.
// This does nothing if SameSiteByDefaultCookies is not enabled.
NET_EXPORT extern const base::Feature
    kRecentCreationTimeGrantsLegacyCookieSemantics;
NET_EXPORT extern const base::FeatureParam<int>
    kRecentCreationTimeGrantsLegacyCookieSemanticsMilliseconds;

// When enabled, blocks external requests coming from non-secure contexts. An
// external request is a request that crosses a network boundary from a more
// public address space into a less public address space.
NET_EXPORT extern const base::Feature
    kBlockExternalRequestsFromNonSecureInitiators;

#if BUILDFLAG(BUILTIN_CERT_VERIFIER_FEATURE_SUPPORTED)
// When enabled, use the builtin cert verifier instead of the platform verifier.
NET_EXPORT extern const base::Feature kCertVerifierBuiltinFeature;
#endif

NET_EXPORT extern const base::Feature kAppendFrameOriginToNetworkIsolationKey;

NET_EXPORT extern const base::Feature
    kUseRegistrableDomainInNetworkIsolationKey;

// Turns off streaming media caching to disk.
NET_EXPORT extern const base::Feature kTurnOffStreamingMediaCaching;

// When enabled, sites that use TLS versions below the |version_min_warn|
// threshold are marked with the LEGACY_TLS CertStatus and return an
// ERR_SSL_OBSOLETE_VERSION error. This is used to trigger an interstitial
// warning for these pages.
NET_EXPORT extern const base::Feature kLegacyTLSEnforced;

// When enabled this feature will cause same-site calculations to take into
// account the scheme of the site-for-cookies and the request/response url.
NET_EXPORT extern const base::Feature kSchemefulSameSite;

// When enabled, TLS connections will initially not offer 3DES and SHA-1 but
// enable them on fallback. This is used to improve metrics around usage of
// those algorithms. If disabled, the algorithms will always be offered.
NET_EXPORT extern const base::Feature kTLSLegacyCryptoFallbackForMetrics;

}  // namespace features
}  // namespace net

#endif  // NET_BASE_FEATURES_H_